when I save a document, files in floating tabs in the back pop to the front!

This issue is making me nuts! When I save a file I'm working on, if I have documents open in floating tabs, the one I just saved goes to the back of the screen and a random floating tab that I'm not even working on pops to the front of the file I AM working on. It's forcing me to reselect the file I was just working on and this is very frustrating since sometimes I'll accidently do something to the file that just popped up in front wihtout realizing it. This seems to be a bug, it's never happened before and there's nothing in the preferences that addresses this. Video attached. 

(I need to work in floating tabs  since I'm often dragging and droppping from one file to another. Consolidating all my windows every time I need to save is not a realistic workflow for me.